So can you just use a crossover cable for private cluster communications between CCR (& SCC) nodes. Well the answer, not very surprisingly, is yes; but there are a couple of caveats…
Be careful and test the cable, especially if it’s a DIY job; And make sure you get speed and duplex settings right:
“If you have a network adapter that can be manually configured to specify speed and duplex mode, and you are using a crossover cable, you should manually specify a speed and duplex mode. With network adapters that can manually specify a speed and duplex mode, make sure that you hard set them with the same configuration on all nodes and according to the manufacturers' specifications. For network adapters that do not support manual settings, follow the card manufacturer's specifications. The amount of information that is travelling across the private network is small, but latency is critical for communication. If you have the same speed and duplex settings, this helps to support reliable communication….”
from ‘How to Configure Network Connections for Cluster Continuous Replication’ @ http://technet.microsoft.com/en-us/library/aa997910.aspx
..and just in case you don’t know how..!